Highly abrasion-resistant grafted polyolefin pipe

ABSTRACT

A pipe- or tube-shaped article comprising an innermost layer made from a grafted polyolefin composition is disclosed which can provide long lifetime, highly abrasion-resistant pipes for mining and other transportation uses. Methods for preparing the article and transporting abrasive materials through the article are also described.

This application is a continuation-in-part of application Ser. No.12/263,161, filed Oct. 31, 2008, now abandoned; the entire disclosure ofwhich is incorporated herein by reference.

The invention relates to highly abrasion-resistant tubular articlescomprising grafted polyolefin layers that provide for the transport ofparticulates and slurries, methods and compositions to produce thearticles, and methods of transporting abrasive materials through them.

BACKGROUND OF THE INVENTION

Mining operations require the transport of highly abrasive particulateor slurry streams. The recovery of bitumen from oil sands is becomingincreasingly important within the energy industry. Processing oil sandincludes transporting and conditioning the oil sand as an aqueous slurryover kilometer lengths of pipe up to 1 meter in diameter. Processes forrecovery of bitumen from oil sands are known (U.S. Pat. Nos. 4,255,433,4,414,117, 4,512,956, 4,533,459, 5,039,227, 6,007,708, 6,096,192,6,110,359, 6,277,269, 6,391,190, US2006/0016760, US2006/0249431,US2007/0023323, US2007/0025896, WO2006/060917, CA1251146, CA2195604,CA2227667, CA2420034, CA2445645, and CA2520943). Use of caustic toassist in the recovery process of oil from oil sands is also known(US2006/0016760 and US2006/0249431). Other mining operations thatinclude the transport of highly abrasive particulate or slurry streamsfrom the mine to processing refinery include, for example, iron ore,coal and coal dust, and the like, and in further non-mining transportprocesses, such as grain, sugar and the like.

Often, metal pipes, such as carbon steel or cast iron pipes, are usedfor the transport of these highly abrasive streams. They are expensive,heavy and only provide a temporary solution since they are eventuallydestroyed. To increase their lifetimes, the metal pipes may be rotated90 degrees on their axes on a regular basis to provide a new transportsurface. However, because of the pipe weight, this rotation is difficultand ultimately the entire pipe is worn out and must be replaced.

Use of plastic pipes, pipe liners and pipe coatings has been proposed toreduce these shortcomings. Material selection is critical. Many of thecommonly available materials cannot stand up to such highly-abrasivemining streams and are quickly worn out. For example, high densitypoly(ethylene) pipes are generally used as liners for sanitary sewer andwastewater pipelines but they rapidly degrade under highly abrasiveenvironments. U.S. Pat. No. 4,042,559 discloses abrasive granule-filled,partially-cured coatings for use in abrasion resistant coated pipes forthe transport of mining slurries. U.S. Pat. No. 4,254,165 disclosesprocesses to produce abrasion resistant pipes with 0.04-0.05-inch thickcoatings of filled (such as sand) polyolefins, such as low and mediumdensity poly(ethylene) and including poly(ethylene-co-acrylic acid).U.S. Pat. No. 4,339,506, WO90/10032, and CA1232553 disclose rubberliners for pipes. U.S. Pat. No. 4,215,178 disclosesfluoropolymer-modified rubber pipe liners. US2006/0137757 andUS2007/0141285 disclose fluoropolymer pipe liners. Polyurethane pipecoatings are known (U.S. Pat. No. 3,862,921, U.S. Pat. No. 4,025,670,US2005/0194718, US2008/0174110, GB2028461, JP02189379, JP03155937, andJP60197770). US2005/0189028 discloses metal pipe coated with apolyurethane liner to transport tar sand slurry. GB2028461 discloses anabrasion-resistant pipe lining comprising a urethane rubber thermosetembedded with the particles of the material to be transported (coaldust, grain or sugar) through transport of the materials during curing.Abrasion resistant pipes with elastomeric polyurea coatings aredisclosed in U.S. Pat. No. 6,737,134. A shortcoming of the polyurethanecoatings includes the highly complex processes for applying the coatingto the metal pipe.

Use of grafted polyolefin compositions made from polyolefins graftedwith an α-olefin monomer and α,β-ethylenically unsaturated carboxylicacid or anhydride as pipes, pipe liners and pipe coatings is known. Forexample, U.S. Pat. No. 4,481,239 discloses polyethylene powder coatingsfor pipes which may include an adhesive layer comprising certain acidcopolymer powder coatings. U.S. Pat. Nos. 4,732,632, 5,178,902,5,279,864, 6,224,710, 6,294,597, 6,976,510, US2005/0217747, US005/0257848 and US2006/0108016 disclose corrosion and mechanicaldamage-resistant pipe coatings for pipe surfaces in which polyolefinswith acrylate or maleic acid groups may be used as adhesives. U.S. Pat.No. 4,737,547 discloses films and pipes comprising blends which mayinclude carboxylic acid- or maleic anhydride-grafted polyolefins.

U.S. Pat. No. 3,616,019, 3,619,320, 3,634,166 and 4,232,086 disclose theuse of carboxyl-modified polyolefins as adhesives for polymeric metalcoatings. U.S. Pat. Nos. 3,932,368, 4,237,037, 4,345,004 and 4,910,046disclose polyolefin powder coatings for metal substrates which mayinclude polar group modified olefinic resins, such as carboxyl- oranhydride-modified resins. U.S. Pat. Nos. 4,048,355, 4,049,904,4,092,452 and 4,824,736 disclose a metal coating of a modifiedpolyolefin grafted with a carboxylic acid or anhydride. U.S. Pat. No.5,091,260 discloses a corrosion-resistant coating for metal substratescomprising 30-99 wt % metallic zinc and a carboxylic acid-graftedpolyolefin. U.S. Pat. No. 5,211,990 disclose a flame spraying process ofpolyolefin powders onto metal substrates that include polyolefinsgrafted with acid or anhydride functionality and ethylene/(meth)acrylicacid copolymers and ionomers derived therefrom. U.S. Pat. No. 5,275,848discloses a powder coating process for metal substrates with polyolefinpowders that include polyolefins grafted with acid or anhydridefunctionality and ethylene/(meth)acrylic acid copolymers and ionomersderived therefrom. U.S. Pat. No. 5,677,377 and U.S. Pat. No. 5,677,378disclose corrosion-resistant powder coatings for steel plate whichinclude maleic anhydride-grafted polypropylene powder. U.S. Pat. No.5,976,652 discloses corrosion-resistant polypropylene film coatings forsteel containers adhered with carboxylic acid- or anhydride-functionalpolypropylenes.

A shortcoming of grafted polyolefin pipes, pipe liners and coatings inthe art is low abrasion resistance resulting in short service lifetimes.

SUMMARY OF THE INVENTION

The invention is directed to a pipe- or tube-shaped article having aninnermost layer wherein the innermost layer has a thickness of about0.001 to about 102 mm and comprises a grafted polyolefin composition;and the innermost layer can have little or no weight loss measured witha wear test disclosed below.

the grafted polyolefin is produced from a parent polyolefin comprisingethylene and an α-olefin with 3 to 20 carbons having a density of about0.92 g/cc (ASTM D-792) or less, grafted with about 0.005 to about 10 wt% of an α,β-ethylenically unsaturated carboxylic acid or anhydride; andhas a Shore A hardness of about 96 or less (ASTM D2240, ISO 868).

The invention is also directed to a method for producing a graftedpolyolefin-lined metal or plastic pipe comprising the step of pulling orinserting a pre-formed grafted polyolefin pipe or multilayer graftedpolyolefin pipe into a preformed metal or plastic pipe wherein thearticle is characterized above.

The invention also provides a method to produce a graftedpolyolefin-lined metal or plastic pipe comprising the step of laying upa pre-formed grafted polyolefin film or sheet or multilayer graftedpolyolefin film or sheet into a preformed metal or plastic pipe whereinthe article is characterized above.

The invention also provides a method for transporting an abrasivematerial comprising obtaining a pipe- or tube-shaped article asdescribed above; preparing an abrasive material composition suitable forflowing through the article; flowing the abrasive material compositioninto one end of the pipe- or tube-formed article and receiving theabrasive material composition out of the other end of pipe- ortube-formed article.

DETAILED DESCRIPTION OF THE INVENTION

All publications, patent applications, patents, and other referencesmentioned herein are incorporated by reference in their entirety. Unlessotherwise defined, all technical and scientific terms used herein havethe same meaning as commonly understood by one of ordinary skill in theart to which this invention belongs.

Trademarks are in upper case.

The term “abrasive” or “abrasive article” has its plain meaning.

Although methods and materials similar or equivalent to those describedherein can be used in the practice or testing of the present invention,suitable methods and materials are described herein.

Unless stated otherwise, all percentages, parts, ratios, etc., are byweight. When an amount, concentration, or other value or parameter isgiven as either a range, preferred range or a list of upper preferablevalues and lower preferable values, this is to be understood asspecifically disclosing all ranges formed from any pair of any upperrange limit or preferred value and any lower range limit or preferredvalue, regardless of whether ranges are separately disclosed. Where arange of numerical values is recited herein, unless otherwise stated,the range is intended to include the endpoints thereof, and all integersand fractions within the range. It is not intended that the scope of theinvention be limited to the specific values recited when defining arange.

In describing certain polymers, sometimes applicants are referring tothe polymers by the monomers used to make them or the amounts of themonomers used to make them. While such a description may not include thespecific nomenclature used to describe the final polymer or may notcontain product-by-process terminology, any such reference to monomersand amounts should be interpreted to mean that the polymer is made fromthose monomers or that amount of the monomers, and the correspondingpolymers and compositions thereof.

The graft copolymer compositions and methods described herein may beused to provide long lifetime, highly abrasion-resistant pipes for awide variety of mining and other transportation uses over a wide rangeof environmental conditions. High burst strength may be anotherattribute of the pipes.

Grafted Polyolefin Layer Composition

By thermoplastic grafted polyolefin polymer, grafted polyolefin andsimilar terms, reference is made to a thermoplastic grafted polyolefinmade from a parent polyolefin made from ethylene and an α-olefin having3 to 20 carbons having a density of about 0.92 g/cc (ASTM D792) or less,grafted with about 0.005 to about 10 wt % of an α,β-ethylenicallyunsaturated carboxylic acid or anhydride; and having a Shore A hardnessof about 96 or less (ASTM D2240, ISO 868). The grafted polyolefin ismade by grafting the α,β-ethylenically unsaturated carboxylic acid oranhydride onto the parent polyolefin.

Regardless of the density a parent polyolefin is, only the innermostlayer having little or no weight loss can be useful in thetransportation of abrasive particulate or slurry stream to prolong thelife of a pipe. The term “little or no loss” refers to an improvement orreduction in weight loss, as compared to the weight loss of using a filmor sheet made from a high density polyethylene having a density of about0.95 or 0.96 utilizing the wear test as described below. The improvementor reduction, in weight loss test can be at least about 30%, at leastabout 50%, at least about 60%, at least about 70%, at least about 80% orat least about 90%.

The improvement or reduction, regardless how weight loss test is done,can be carried out with a wear test coupon. The test coupon may be anysize or shape. For example, it can be rectangular, square, trapezoid, ortriangular. Also for example, it can be relatively large or small. Forillustrative, it may be 1 inch square and 0.1 inch thick or 50 mm squareby 6 mm thick. The size and shape depend on one's preference. The testcoupon can be cut from injection molded plaque, film, or sheet of theinner layer (i.e., the grafted polyolefin).

As disclosed herein, the wear test coupon can be dried according toone's preference such as in a vacuum oven at, for example, 20 inches Hgand a temperature of from room temperature (about 20-25° C.) to about50° C. such as at 35° C. until the weight becomes almost or aboutconstant. The wear test coupon can be mounted in a test chamber with animpinging abrasive particulate or slurry, such as an aqueous sand (forexample, a AFS50-70 test sand) slurry at any desired temperature such asroom temperature (20-25° C.) on the wear test coupon through a slurryjet nozzle positioned a certain distance about 4 to 20 inch from itssurface with a diameter of 0.1 to about 1 inch at a relatively moderateor high slurry jet rate of, for example, 15-16 meters/second with aslurry jet angle of, for example, 90° relative to the surface plane forabout 1 to about 10 hours.

The grafted polyolefin is made from a parent polyolefin that has adensity of about 0.92 g/cc (ASTM D-792) or less, about 0.90 g/cc orless, about 0.88 g/cc or less, about 0.87 g/cc or less, about 0.86 g/ccor less, about 0.84 to about 0.87 g/cc, or about 0.84 to about 0.86g/cc.

The parent polyolefin is a polyolefin copolymer comprising ethylene andα-olefin comonomers. The polyolefin copolymer comprises at least twomonomers, but may incorporate more than two comonomers, such asterpolymers, tetrapolymers and the like. Preferably, the polyolefincopolymer comprises from about 5 wt % to about 50 wt % of the α-olefincomonomer (based on the total weight of the polyolefin copolymer), about15 wt % to about 45 wt %, about 20 wt % to about 40 wt %, or about 25 wt% to about 35 wt %.

The α-olefin comonomer contains from 3 to 20 carbons and may be alinear, branched or cyclic α-olefin such as selected from the groupconsisting of propene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene,1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene,1-hexadecene, 1-octadecene, 3-cyclohexyl-1-propene, vinyl cyclohexane,and combinations of two or more thereof. The α-olefin comonomerpreferably contains 3 to 10 carbons.

The polyolefin copolymer may optionally incorporate a minor amount ofother olefinic comonomers; for example cyclic olefins such asnorbornene; styrene; dienes such as dicyclopentadiene, ethylidenenorbornene and vinyl norbornene; and the like and mixtures thereof. Whenincluded, the optional comonomer may be incorporated at a level of about15 wt % or less, based on the total weight of the polyolefin copolymer.

The polyolefin may be produced by any known method and may be catalyzedwith any known polymerization catalyst such as, for example, radical-,Ziegler-Natta- or metallocene-catalyzed polymerizations (e.g., U.S. Pat.Nos. 3,645,992, 5,026,798, 5,055,438, 5,057,475, 5,064,802, 5,096,867,5,132,380, 5,231,106, 5,272,236, 5,278,272, 5,374,696, 5,420,220,5,453,410, 5,470,993, 5,703,187, 5,986,028, 6,013,819, 6,159,608, andEP514828.

Blends of two or more polyolefin copolymers may be used, if desired, aslong as the density of the blend meets the requirements set forth abovefor the single polyolefin copolymer.

The grafted polyolefin comprises an α,β-ethylenically unsaturatedcarboxylic acid or anhydride grafted to the parent polyolefin. Theα,β-ethylenically unsaturated carboxylic acid or anhydride preferably isselected from the group consisting of maleic anhydride, maleic acid,fumaric acid, acrylic acid, methacrylic acid, itaconic anhydride,itaconic acid, citraconic acid, citraconic anhydride, crotonic acid,crotonic anhydride, methyl crotonic acid, cinnamic acid,endo-bicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic acid,endo-bicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic anhydride,cis-4-cyclohexene-1,2-dicarboxylic acid,cis-4-cyclohexene-1,2-dicarboxylic anhydride and the like and mixturesthereof. Metal salts, anhydrides, esters, amides or imides of the aboveacids may also be used. More preferably, the α,β-ethylenicallyunsaturated carboxylic acid or anhydride is maleic anhydride.

The α,β-ethylenically unsaturated carboxylic acid or anhydride may begrafted onto the parent polyolefin by any known method. For example, theα,β-ethylenically unsaturated carboxylic acid or anhydride may begrafted onto the parent polyolefin by the methods disclosed in U.S. Pat.Nos. 3,236,917, 3,932,368, 4,612,155, 4,888,394, 4,950,541, 5,194,509,5,346,963, 5,523,358, 5,705,565, 5,744,250, 5,955,547, 6,545,091,7,408,007, US2008/0078445, US2008/0115825, and EP0266994.

The level of the α,β-ethylenically unsaturated carboxylic acid oranhydride grafted onto the parent polyolefin is preferably from about0.005 to 10 wt %, based on the total weight of the grafted polyolefin.The level of the α,β-ethylenically unsaturated carboxylic acid oranhydride may be from about 0.03 to 5 wt % or from about 0.1 to 2 wt %,based on the total weight of the grafted polyolefin. The level of thegrafted α,β-ethylenically unsaturated carboxylic acid or anhydride maybe optimized to provide the desirable adhesion to other substrates, suchas a metal pipe.

The grafted polyolefin may have Shore A hardness of about 96 or less(ASTM D2240, ISO 868), about 80 or less, about 70 or less, or about 70to about 50. The grafted polyolefin may be blended with furtherpolymeric materials as long as the Shore A hardness of the blendconforms to the above requirements. The blend preferably comprises thegrafted polyolefin with a polyolefin selected from the group consistingof the parent polyolefin copolymers, as described above.

The compositions may be used with additives known in the art. Theadditives include plasticizers, processing aids, flow enhancingadditives, flow reducing additives, lubricants, flame retardants, impactmodifiers, nucleating agents to increase crystallinity, antiblockingagents such as silica, thermal stabilizers, UV absorbers, UVstabilizers, dispersants, surfactants, chelating agents, couplingagents, adhesives, primers and the like. One of ordinary skill in theart will recognize that additives may be added to the grafted polyolefincomposition using techniques known in the art or variants thereof, andwill know the proper amounts for addition based upon typical usage. Thetotal amount of additives used in a grafted polyolefin composition maybe up to about 15 weight % (based upon the weight of the graftedpolyolefin composition).

However, a tackifier or tackifier resin such as a variety of natural andsynthetic resins and rosin materials. Such tackifier may be liquid,semi-solid to solid, or solid, including complex amorphous materialsgenerally in the form of mixtures of organic compounds having nodefinite melting point and no tendency to crystallize. Such resins canprovide substantial and improved tackiness to the composition and maydiffuse out of the composition during the production of the pipedisclosed herein. Other tackifiers include para-coumarone-indene resins,(poly)terpene resins, butadiene-styrene resins, polybutadiene resins,hydrocarbon resins, or rosins.

The grafted polyolefin compositions may contain additives thateffectively reduce the melt flow of the resin, which may be present inany amount that permits production of thermoset compositions. The use ofsuch additives will enhance the upper end-use temperature and reducecreep of the pipes produced therefrom. The cured grafted polyolefincompositions may have enhanced resistance to the low molecular weightaromatic fraction and naptha commonly contained in oil sand slurries.

Melt flow reducing additives include organic peroxides, such as2,5-dimethylhexane-2,5-dihydroperoxide,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane-3, di-tert-butyl peroxide,tert-butylcumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane,dicumyl peroxide, α,α′-bis(tert-butyl-peroxyisopropyl)benzene,n-butyl-4,4-bis(tert-butylperoxy)valerate,2,2-bis(tert-butylperoxy)butane, 1,1-bis(tert-butyl-peroxy)cyclohexane,1,1-bis(tert-butylperoxy)-3,3,5-trimethyl-cyclohexane, tert-butylperoxybenzoate, benzoyl peroxide, and the like and mixtures combinationsthereof. Preferably the organic peroxides decompose at a temperature ofabout 100° C. or higher to generate radicals. More preferably, theorganic peroxides have a decomposition temperature that affords a halflife of 10 hours at about 70° C. or higher to provide improved stabilityfor blending operations. The organic peroxides may be added at a levelof about 0.01 to about 10 wt %, or about 0.5 to about 3 wt %, based onthe total weight of the grafted polyolefin composition.

If desired, initiators such as dibutyltin dilaurate may also be presentin the grafted polyolefin composition at about 0.01 to about 0.05 wt %,based on the total weight of the grafted polyolefin composition. Also ifdesired, inhibitors such as hydroquinone, hydroquinone monomethyl ether,p-benzoquinone, and methylhydroquinone may be added for the purpose ofenhancing control to the reaction and stability. The inhibitors may beadded at a level of less than about 5 wt %, based on the total weight ofthe composition.

Alternative melt flow reducing additives include known peroxide-silanoladditives which commonly include a peroxide (as described above), asilane and a catalyst. These additive systems provide moisture curablematerials. Such systems may be added in a concentrate form, such ascommercially available under the SILCAT trademark (Momentive PerformanceMaterials, Wilton, Conn., USA).

The grafted polyolefin composition may further comprise about 0.1 toabout 80 weight % filler based on the total weight of the filledcomposition.

Preferably, the filler is abrasion-resistant filler. The filler may bereinforcing filler or non-reinforcing filler. Specific examples ofpreferred reinforcing fillers include high strength fibers such asfiberglass, continuous glass fiber, polyaramide fiber, KEVLAR (aramidfiber, a product of E. I. du Pont de Nemours and Company (DuPont), oneor more fibers made from one or more aromatic polyamides, wherein atleast 85% of the amide (—CONH—) linkages are attached directly to twoaromatic rings), graphite, carbon fiber, silica, quartz, ceramic,silicon carbide, boron, alumina, alumina-silica, polyethylene, ultrahighmolecular weight polyethylene, polyimide, liquid crystal polymers,polypropylene, polyester, polyamide and the like. For example,US2006/0124188 and US2006/0151042 disclose fiber-reinforced pipe liners.Specific examples of non-reinforcing fillers include particles ofabrasion-resistant minerals, marble, slate, granite, sand, potters'sand, silicates, limestone, clay, glass, quartz, metallic powders,aluminum powders, stainless steel powders, zinc metal, refractory metalborides (such as borides of aluminum, niobium, silicon, tantalum,titanium, tungsten, and zirconium), carbides (such as carbides of boron,niobium, silicon, tantalum, titanium, tungsten and zirconium), nitrides(such as nitrides of aluminum, boron, niobium, silicon, tantalum,titanium, tungsten and zirconium), oxides (such as oxides of aluminum,niobium, silicon, tantalum, titanium, tungsten and zirconium), siliconcarbide, alumina, fused combinations of alumina and zirconia, calciumcarbonate, barium sulfate, magnesium silicate and the like andcombinations thereof.

The size of the filler incorporated in the grafted polyolefincomposition depends on the thickness and diameter of the graftedpolyolefin pipe and should be smaller than the thickness of the graftedpolyolefin pipe. Preferably, a mixture of particle sizes is used toprovide a higher density (percentage by volume) of filler incorporated.For abrasion-resistant fillers, this may result in a higher abrasionresistance of the filled grafted polyolefin pipe. Filled polymeric pipesare known (U.S. Pat. Nos. 3,498,827, 4,042,559, 4,254,165, 4,407,893,5,091,260, 5,562,989, and GB 2028461).

Grafted Polyolefin Pipe

The article in the form of a pipe comprising the grafted polyolefincomposition comprises an innermost layer having a thickness of about0.001 to about 102 mm (about 0.00004 to about 4 inches) of the graftedpolyolefin composition. The pipe may have a hollow circular profile andthe wall thickness may be generally uniform around the circumference ofthe pipe. This should not be taken as limiting. The pipe may have anyprofile and the wall thickness may vary around the circumference of thepipe as desired. The grafted polyolefin composition is positioned as theinnermost layer to provide superior abrasion-resistance. The graftedpolyolefin pipe thickness provides not only a long lifetime underextreme abrasive end-use conditions, but also provides desirable highburst strength under the high temperature conditions contemplatedherein. Preferably, the grafted polyolefin layer has a thickness ofabout 3.2 to about 102 mm (about 0.125 to about 4 inches), or about 6.3to about 76 mm (about 0.25 to about 3 inches), or about 13 to about 51mm (about 0.5 to about 2 inches) to provide greater levels of end-uselifetime, burst strength and temperature resistance.

The grafted polyolefin pipe may have any dimensions (including outsidediameter, inside diameter and length) required to meet the end useneeds. For example but not limitation, the grafted polyolefin pipepreferably has an outer diameter (OD) of about 2.54 to about 254 cm(about 1 to about 100 inches), more preferably, about 25.4 to about 152cm (about 10 to about 60 inches) and most preferably, about 51 to about102 cm (about 20 to about 40 inches). For example but not limitation thegrafted polyolefin pipe preferably has a length of about 1.5 to about12.2 m (about 5 to about 40 feet), more preferably about 3.1 to about9.1 m (about 10 to about 30 feet) and most preferably about 5.5 to about6.7 m (about 18 to 22 feet) to provide a convenient length for storage,transport, handling and installation.

The grafted polyolefin pipe may be produced by any suitable process. Forexample, the grafted polyolefin pipe may be formed by melt extrusion,melt coextrusion, slush molding, rotomolding, rotational molding or anyother procedures known in the art. For example, the grafted polyolefinpipe may be produced by rotational or slush molding processes. Thegrafted polyolefin composition may be in the form of powder, microbeadsor pellets for use in rotational molding processes. Methods forrotational molding of pipes are known (U.S. Pat. No. 4,115,508, U.S.Pat. No. 4,668,461, and ZA9607413). For example, ZA9607413 discloseswear-resistant composite pipe linings produced through rotationalmolding a mixture of a polymeric material with an abrasion-resistantparticulate material. Methods for rotational molding with polymerpowders are known (U.S. Pat. Nos. 3,784,668; 3,876,613; 3,891,597;3,974,114; 4,029,729; 4,877,562; 5,366,675; 5,367,025 and 5,759,472).U.S. Pat. No. 3,974,114 discloses rotational molding of articles withpoly(ethylene-co-acrylic acid) copolymer powders. Methods for rotationalmolding with polymer microbeads are known (U.S. Pat. No. 5,886,068;EP1422059; and EP1736502). U.S. Pat. No. 5,886,068 discloses rotationalmolding processes using blends of micropellets. Methods for rotationalmolding with polymer pellets are known (U.S. Pat. Nos. 4,032,600;4,185,067; 5,232,644; and EP0778088). Methods for slush molding withpolymer powders are known (U.S. Pat. No. 6,218,474 and EP1169390).

Preferably, the grafted polyolefin pipes disclosed herein are formed bymelt extrusion and coextrusion processes that are particularly preferredprocesses for formation of “endless” products. Methods for extrudingpolymers in the form of pipe are known (U.S. Pat. Nos. 2,502,638;3,538,209; 3,561,493; 3,755,168; 3,871,807; 3,907,961; 3,936,417;4,069,001; 4,123,487; 4,125,585; 4,196,464; 4,203,880; 4,301,060;4,377,545; 4,402,658; 4,465,449; 4,663,107; 4,888,148; 5,028,376;5,089,204; 5,514,312; 5,518,036; 5,643,526; 5,842,505; 5,976,298;6,174,981; 6,241,840; 6,418,732; 6,469,079; 6,787,207; US20050167892;US20070117932; EP0222199; EP1574772; WO95/07428; WO2000/018562;WO2006/090016; and WO2006/134228). The molten polymer is forced throughan annular die and a mandrel to provide the hollow circular profile ofthe pipe with the inner pipe diameter controlled by the size of themandrel. The diameter of the pipe may also be controlled through theapplication of air pressure inside the pipe. The outer diameter may becontrolled with external sizing dies or sleeves. The pipe is cooled toform the final shape. Multilayer pipe is produced similarly using amultilayer annular die that is fed by two or more extruders.

Multilayer Grafted Polyolefin Pipe.

The article may be in the form of a multilayer pipe comprising aninnermost layer of the grafted polyolefin composition and an outsidelayer comprising a polymeric material. Examples of preferred polymericmaterials for the outside layer include poly(meth)acrylics,polyacrylates, urethane modified polyacrylics, polyester modifiedpolyacrylics, polystyrenes, polyolefins, polyethylenes (such as highdensity polyethylene, low density polyethylene, linear low densitypolyethylene, ultralow density polyethylene), polypropylenes,polyurethanes, polyureas, epoxy resins, polyesters (such aspoly(ethylene terephthalate), poly(1,3-propyl terephthalate),poly(1,4-butylene terephthalate), PETG,poly(ethylene-co-1,4-cyclohexanedimethanol terephthalate)), alkydresins, polyamides (such as nylons, nylon 6, nylon 46, nylon 66, nylon612), polyamideimides, polyvinyls, phenoxy resins, amino resins,melamines, chlorine-containing resins, chlorinated polyethers,fluorine-containing resins, polyvinyl acetals, polyvinyl formals,poly(vinyl butyrate)s, polyacetylenes, polyethers, silicone resins, ABSresins, polysulfones, polyamine sulfones, polyether sulfones,polyphenylene sulfones, polyvinyl chlorides, polyvinylidene chlorides,polyvinyl acetates, polyvinyl alcohols, polyvinyl carbazoles, butyrals,polyphenylene oxides, polypyrroles, polyparaphenylenes,ultraviolet-curing resins, cellulose derivatives, diethylene glycolbis-allyl carbonate poly-4-methylpentene, polytetrafluoroethylene,polytrifluoroethylene, polyvinylidene fluoride,poly(ethylene-co-glycidylmethacrylate), poly(ethylene-co-methyl(meth)acrylate-co-glycidyl acrylate), poly(ethylene-co-n-butylacrylate-co-glycidyl acrylate), poly(ethylene-co-methyl acrylate),poly(ethylene-co-ethyl acrylate), poly(ethylene-co-butyl acrylate), acidcopolymers, acid terpolymers, poly(ethylene-co-(meth)acrylic acid),ionomers, ionomer terpolymers, metal salts ofpoly(ethylene-co-(meth)acrylic acid), poly((meth)acrylates),poly(ethylene-co-carbon monoxide), poly(ethylene-co-vinyl acetate),poly(ethylene-co-vinyl alcohol), polybutylene, poly(cyclic olefins),syndiotactic polystyrene, poly(4-hydroxystyrene), novalacs,poly(cresols), polycarbonates, poly(bisphenol A carbonate),polysulfides, poly(phenylene sulfide), poly(2,6-dimethylphenyleneoxide), elastomers, rubbers, thermoplastic elastomers and the like andcopolymers thereof and mixtures thereof.

More preferably, the polymeric materials are selected from the groupconsisting of rubbers, elastomers, thermoplastic elastomers, acidterpolymers, ionomer terpolymers and the like and combinations thereof.Rubbers and elastomers are generally categorized as diene elastomers,saturated elastomers, thermoplastic elastomers and inorganic elastomers.Specific examples of rubbers and elastomers include natural rubber,polyisoprene, butyl rubber (copolymer of isobutylene and isoprene),polybutadiene, styrene butadiene (SBR, copolymer of polystyrene andpolybutadiene), nitrile rubber (copolymer of polybutadiene andacrylonitrile, also referred to as “buna N rubbers”), silicone RTV, FKMVITON (DuPont) (copolymer of vinylidene fluoride andhexafluoropropylene), SANTOPRENE (Advanced Elastomer Systems, LP, Akron,Ohio), fluorosilicone rubber, EPM and EPDM rubber (ethylene propylenerubber, a copolymer of polyethylene and polypropylene), polyurethanerubber, polyurea rubber, resilin, polyacrylic rubber (ABR),epichlorohydrin rubber (ECO), polysulfide rubber, chlorosulfonatedpolyethylene (CSM, HYPALON (DuPont)) and the like. Thermoplasticelastomers are generally categorized as styreneics (S-TPE), copolyesters(COPE), polyurethanes (TPU), polyamides (PEBA), polyolefin blends (TPO),polyolefin alloys (TPV), reactor TPO(R-TPO), polyolefin plastomers(POP), polyolefin elastomers (POE) and the like. Acid terpolymers aremade from α-olefins, α,β-ethylenically unsaturated carboxylic acids andpreferably about 10 to about 25 wt % other unsaturated comonomers (allas described above).

The polymer material layer may have any thickness. Preferably, thepolymer material layer is about 0.1 to about 102 mm (about 0.004 toabout 4 inches), or about 1 to about 25.4 mm (about 0.04 to about 1inch) or about 2.5 to about 12.7 mm (about 0.1 to about 0.5 inch) thick.

Tielayers may be included between any of the layers to enhance theadhesion between the layers. Any material may be used in tielayers, suchas anhydride- or acid-grafted materials. The preferred anhydrides andacids are α,β-ethylenically unsaturated carboxylic acid comonomersselected from the group consisting of acrylic acid, methacrylic acid,itaconic acid, maleic acid, maleic anhydride, fumaric acid, monomethylmaleic acid, and mixtures thereof. Most preferred anhydrides and acidsare selected from the group consisting of acrylic acid, maleic anhydrideand mixtures thereof. Preferably, the materials to be grafted areselected from the preferred polymeric materials recited above.

Fiber-Reinforced Grafted Polyolefin Pipe

The article may be in the form of a multilayer pipe comprising aninnermost layer having a thickness of about 0.001 to about 102 mm(0.00004 to 4 inches) comprising the grafted polyolefin composition andan outer layer comprising fiber reinforcement and optionally thermosetresin.

The article also may be in the form of a multilayer pipe comprising aninnermost layer having a thickness of about 0.001 to about 102 mm(0.00004 to 4 inches) comprising the grafted polyolefin composition; anintermediate layer comprising a polymeric material; and an outer layercomprising a fiber reinforcement and optionally a thermoset resin.

The fiber reinforcement may be a filament, warp yarn, tape,unidirectional sheet, mat, cloth, knitted cloth, paper, non-woven fabricor woven fabric, or mixtures thereof. The fiber preferably comprises ahigh strength fiber such as fiberglass, continuous glass fiber,polyaramide fiber, aramid fiber, graphite, carbon fiber, silica, quartz,ceramic, silicon carbide, boron, alumina, alumina-silica, polyethylene,ultrahigh molecular weight polyethylene, polyimide, liquid crystalpolymers, polypropylene, polyester, polyamide and the like, and ispreferably about 3 to about 30 μm thick.

The fiber may be impregnated with a resin (“prepreg”), such asthermoplastic or preferably thermoset resins. Suitable resins forimpregnating the fiber layers include polyester, aromatic, aliphatic,cycloaliphatic or anhydride epoxy resins, vinylester, vinyl, acrylic,modified acrylic, urethane, phenolic, polyimide, bismaleimide, polyurea,siloxane-modified resins and the like and combinations thereof.

Fiber-reinforcement of thermoplastic pipe is known (U.S. Pat. Nos.4,081,302; 4,521,465; 5,629,062; 5,931,198; 6,737,134; 7,018,691;US2006/0151042; and WO2004/068016).

An adhesive may be applied to the grafted polyolefin pipe and multilayergrafted polyolefin pipe prior to the application of the exteriorreinforcement layer and/or an adhesive may be applied to thereinforcement layer after its application to the grafted polyolefin pipeand multilayer grafted polyolefin pipe. The exterior surface of thegrafted polyolefin pipe and multilayer grafted polyolefin pipe may beheated to enhance the adhesion and/or embedding of the reinforcementlayer. Suitable adhesives may include the impregnated resins describedabove or any adhesive known in the art.

The fiber reinforcement may be applied to the grafted polyolefin pipeand multilayer grafted polyolefin pipe by any method known in the art.For example, the fiber reinforcement may be applied using known filamentwinding processes through winding the fiber reinforcement onto thegrafted polyolefin pipe and multilayer grafted polyolefin pipe or bywrapping the fiber reinforcement around the grafted polyolefin pipe andmultilayer grafted polyolefin pipe.

Grafted Polyolefin-Lined Metal Pipe

The article may be in the form of a multilayer pipe comprising aninnermost layer having a thickness of about 0.001 to about 102 mm(0.00004 to 4 inches) comprising the grafted polyolefin composition andan outer layer comprising a metal, preferably in the form of a metalpipe.

The monolayer or multilayer grafted polyolefin composition (such as inthe form of pipe, film, or sheet) may be attached (adhered) to the metalouter layer or not attached. The grafted polyolefin or multilayergrafted polyolefin compositions may be self-adhered to the metal layeror adhered through the use of an adhesion primer, coating, or layer. Asused herein, when the grafted polyolefin composition is said to be“self-adhered” to the metal layer, it is meant that there is nointermediate layer such as a primer or thin adhesive layer between themetal and the grafted polyolefin or multilayer grafted polyolefincomposition. The grafted polyolefin compositions described herein havethe advantage of forming high adhesion to the metal pipe.

The pipe may comprise an innermost layer comprising the graftedpolyolefin composition; an intermediate layer comprising a polymermaterial (such as those polymeric materials described above); and anouter layer comprising metal.

The pipe may comprise an innermost layer comprising the graftedpolyolefin composition; an intermediate layer comprising a polymermaterial; and an outer layer comprising metal, wherein the graftedpolyolefin layer is adhered to the polymer material layer and thepolymer material layer is adhered to the metal layer.

The pipe may comprise an innermost layer comprising the graftedpolyolefin composition; an intermediate layer comprising a polymermaterial; and an outer layer comprising metal, wherein the graftedpolyolefin layer is self-adhered to the polymer layer and the polymerlayer is self-adhered to the metal layer.

The pipe may further comprise an intermediate layer comprising a fiberreinforcement material comprising a high strength fiber and optionally athermoset resin as described above.

Preferably, the metal pipe comprises carbon steel, steel, stainlesssteel, cast iron, galvanized steel, aluminum, copper and the like. Morepreferably the metal pipe comprises carbon steel to provide the physicalproperties required for the material conveying processes contemplatedherein.

The metal pipe may have any dimensions, including thickness, outerdiameter, inner diameter and length suitable for the intended use. Thepipe may have a hollow, substantially circular profile and the wallthickness may be generally uniform around the circumference of the pipe,or the pipe may have any profile and the wall thickness may vary aroundthe circumference of the pipe as desired. For example but notlimitation, the metal pipe may have a thickness of about 6.3 to about 51mm (about 0.25 to about 2 inches, about 9.5 to about 38 mm (about 0.375to about 1.5 inches) or about 13 to about 25.4 mm (about 0.5 to about 1inch). For example but not limitation, the metal pipe may have an OD ofabout 5.1 to about 254 cm (about 2 to about 100 inches), about 25.4 toabout 152 cm (about 10 to about 60 inches) or about 51 to about 102 cm(about 20 to about 40 inches). For example but not limitation the metalpipe may have a length of about 1.5 to about 12.2 m (about 5 to about 40feet), about 3.1 to about 9.1 m (about 10 to about 30 feet) or about 5.5to about 6.7 m (about 18 to 22 feet) to provide a convenient length forstorage, transport, handling and installation.

The grafted polyolefin-lined metal pipe may be produced by any knownmethod. For example, the grafted polyolefin pipe and multilayer graftedpolyolefin pipe may serve as a liner for a metal pipe. Methods forlining a pipe with a polymeric liner are known (U.S. Pat. Nos.3,315,348; 3,429,954; 3,534,465; 3,856,905; 3,959,424; 4,207,130;4,394,202; 4,863,365; 4,985,196; 4,998,871; 5,072,622; 5,320,388;5,374,174; 5,395,472; 5,551,484; 5,810,053; 5,861,116; 6,058,978;6,067,844; 6,240,612; 6,723,266; 2006/0093436; 2006/0108016;US2006/0124188; US2006/0151042; and EP0848659).

The inside surface of the metal pipe may be pretreated to provideenhanced adhesion and stability. Such treatments include descaling bysand-, metal grit- or shot-blasting, acid etching, cleaning the metalsurface through solvent or chemical washes to remove grease and/or oxidelayers, and the application of adhesion primers, coatings, or layers.

A grafted polyolefin-lined metal pipe may be prepared by pulling orinserting a preformed grafted polyolefin pipe or multilayer graftedpolyolefin pipe into a preformed metal pipe wherein the outer diameterof the grafted polyolefin pipe is less than the interior diameter of themetal pipe. This method to produce a grafted polyolefin-lined metal pipeincludes the following embodiments.

The method comprises (i) pulling or inserting a pre-formed graftedpolyolefin pipe or multilayer grafted polyolefin pipe into the metalpipe; (ii) heating the grafted polyolefin-lined metal pipe above thesoftening point of the grafted polyolefin composition; and (iii)allowing the metal pipe to cool.

The method comprises (i) heating a metal pipe above the softening pointof the grafted polyolefin composition; (ii) pulling or inserting apre-formed grafted polyolefin pipe or multilayer grafted polyolefin pipeinto the heated metal pipe; and (iii) allowing the metal pipe to cool.

The method comprises (i) coating a layer of an adhesive or adhesionprimer onto the outside surface of the grafted polyolefin pipe ormultilayer grafted polyolefin pipe; and (ii) pulling or inserting theadhesive-treated grafted polyolefin pipe or multilayer graftedpolyolefin pipe into the metal pipe.

The method comprises (i) coating a layer of an adhesive or adhesionprimer onto the inside surface of the metal pipe; and (ii) pulling orinserting the grafted polyolefin pipe or multilayer grafted polyolefinpipe into the adhesive-treated metal pipe.

The method comprises (i) coating a layer of an adhesive or adhesionprimer onto the outside surface of the grafted polyolefin pipe ormultilayer grafted polyolefin pipe; (ii) pulling or inserting theadhesive-treated grafted polyolefin pipe or multilayer graftedpolyolefin pipe into the metal pipe; (ii) heating the metal pipe abovethe softening point of the grafted polyolefin composition; and (iv)allowing the metal pipe to cool.

The method comprises (i) coating a layer of an adhesive or adhesionprimer onto the inside surface of the metal pipe; (ii) pulling orinserting the grafted polyolefin pipe or multilayer grafted polyolefinpipe into the adhesive-treated metal pipe; (iii) heating the metal pipeabove the softening point of the grafted polyolefin composition; and(iv) allowing the metal pipe to cool.

The method comprises (i) coating a layer of an adhesive or adhesionprimer onto the outside surface of the grafted polyolefin pipe ormultilayer grafted polyolefin pipe; (ii) heating a metal pipe above thesoftening point of the grafted polyolefin composition; (iii) pulling orinserting the adhesive-treated grafted polyolefin pipe or multilayergrafted polyolefin pipe into the heated metal pipe; and (iv) allowingthe metal pipe to cool.

The method comprises (i) coating a layer of an adhesive or adhesionprimer onto the inside surface of the metal pipe; (ii) heating theadhesively-treated metal pipe above the softening point of the graftedpolyolefin composition; (iii) pulling or inserting the graftedpolyolefin pipe or multilayer grafted polyolefin pipe into the heatedmetal pipe; and (iv) allowing the metal pipe to cool.

In a specific embodiment, the method for adhering the grafted polyolefinpipe or multilayer grafted polyolefin pipe to the metal pipe comprises(a) descaling and cleaning the interior surface of the metal pipe; (b)heating the metal pipe to a temperature of about 150 to about 400° C.,preferably about 150 to about 300° C. and most preferably of about 175to about 225° C.; (c) pulling or inserting the grafted polyolefin liner(pipe) or grafted polyolefin multilayer liner (pipe) into the hot metalpipe; and (d) allowing the grafted polyolefin-lined metal pipe to coolto ambient conditions.

For example, preparing a grafted polyolefin lined metal pipe with aself-adhered grafted polyolefin liner (pipe) includes descaling theinterior of the metal pipe, followed by degreasing and cleaning Themetal pipe is then heated, as in an oven, a furnace, a gas ring burner,electrical resistive heating elements, radiant heaters, inductionheating, high frequency electrical heaters and the like, and the heatingmay be discontinued throughout the remainder of the process or the metalpipe may be continuously heated, as through induction heating,throughout the process. The heating expands the metal pipe. A graftedpolyolefin liner (pipe) or grafted polyolefin multilayer liner (pipe) ispulled or inserted into the hot metal pipe. The grafted polyolefin ormultilayer grafted polyolefin liner preferably has an outside diameter(OD) that is no greater than about 0.1 inch (2.5 mm) less than theinside diameter (ID) of the unheated metal pipe, more preferably an ODno greater than about 0.05 inch (1.3 mm) less than the ID, even morepreferably, an OD no greater than about 0.025 inch (0.64 mm) less thanthe ID. Most preferably, the grafted polyolefin and multilayer graftedpolyolefin liner OD is about equivalent to the ID of the unheated metalpipe. As the heated metal pipe-grafted polyolefin liner structure cools,the metal pipe reduces in diameter and makes intimate contact with theoutside surface of the grafted polyolefin liner, causing it to softenand self-adhere to the inside surface of the metal pipe. Alternatively,the grafted polyolefin liner (pipe) or multilayer grafted polyolefinliner (pipe) may be inserted into the metal pipe prior to heating.

If desired, prior to heating the metal pipe and inserting the graftedpolyolefin and multilayer grafted polyolefin liner (pipe), an adhesiveprimer, coating or layer may be applied to the interior surface of themetal pipe, the exterior surface of the grafted polyolefin andmultilayer grafted polyolefin liner, or both, in the form of a solutionor solid to provide enhanced interlayer adhesion.

A method to produce a grafted polyolefin-lined metal pipe compriseslaying up a preformed grafted polyolefin film or sheet or multilayergrafted polyolefin film or sheet into a preformed metal pipe. Thismethod to produce a grafted polyolefin-lined metal pipe includes thefollowing embodiments.

The method comprises (i) laying up the interior of a metal pipe withgrafted polyolefin film or sheet or multilayer grafted polyolefin filmor sheet; (ii) heating a metal pipe above the softening point of thegrafted polyolefin composition; and (iii) allowing the metal pipe tocool.

The method comprises (i) coating a layer of an adhesive or adhesionprimer onto the outside surface of the grafted polyolefin film or sheetor multilayer grafted polyolefin film or sheet; and (ii) laying up theinterior of a metal pipe with grafted polyolefin film or sheet ormultilayer grafted polyolefin film or sheet.

The method comprises (i) coating a layer of an adhesive or adhesionprimer onto the inside surface of the metal pipe; and (ii) laying up theinterior of a metal pipe with grafted polyolefin film or sheet ormultilayer grafted polyolefin film or sheet.

The method comprises (i) coating a layer of an adhesive or adhesionprimer onto the outside surface of the grafted polyolefin film or sheetor multilayer grafted polyolefin film or sheet; (ii) laying up theinterior of a metal pipe with grafted polyolefin film or sheet ormultilayer grafted polyolefin film or sheet; (iii) heating a metal pipeabove the softening point of the grafted polyolefin composition; and(iv) allowing the metal pipe to cool.

The grafted polyolefin film or sheet and the multilayer graftedpolyolefin film or sheet may be produced by any art method. Preferablythe film or sheet is produced through melt processes, such as extrusionblown film processes, extrusion film or sheet melt casting processes,sheet profile extrusion processes, calendar processes and the like. Thefilms and sheets may undergo secondary formation processes, such as theplying together of preformed sheets to produce thicker sheets throughknown calendaring processes.

An example method for preparing grafted polyolefin lined metal pipe witha self-adhered grafted polyolefin sheet includes descaling the interiorof the metal pipe, followed by degreasing and cleaning The interior ofthe metal pipe is then covered with the grafted polyolefin sheet,preferably with the sheet overlapping onto itself 0.5 to 4 inches toform a seam. The seam may be heat fused or the excess sheet may betrimmed and the sheet ends may be heat fused, as desired. The metal pipeis then heated, as described above, to the temperature range of about150 to about 400° C., preferably to the temperature range of about 150to about 300° C. and most preferably to the temperature range of about175 to about 225° C. As the heated metal pipe-grafted polyolefin sheetstructure cools, the metal pipe makes intimate contact with the outsidesurface of the grafted polyolefin sheet, causing it to soften andself-adhere to the inside surface of the metal pipe.

If desired, prior to heating the metal pipe and inserting the graftedpolyolefin and multilayer grafted polyolefin film or sheet, an adhesiveprimer, coating or layer may be applied to the interior surface of themetal pipe, the exterior surface of the grafted polyolefin andmultilayer grafted polyolefin film or sheet or both, in the form of asolution or solid to provide enhanced interlayer adhesion.

The grafted polyolefin-lined metal pipe may be produced by powdercoating processes. Methods for coating the inner or outer surfaces of apipe with polymeric powder coatings are known (U.S. Pat. Nos. 3,004,861;3,016,875; 3,063,860; 3,074,808; 3,138,483; 3,186,860; 3,207,618;3,230,105; 3,245,824; 3,307,996; 3,488,206; 3,532,531; 3,974,306;3,982,050; 4,007,298; 4,481,239; and EP778088). For example, U.S. Pat.No. 4,407,893 discloses powder coating processes to produceabrasion-resistant pipes with 0.04-inch thick coatings of sand-filledblends comprising polyethylenes and ionomers.

The grafted polyolefin composition may be produced in the form of apowder by any known method. Methods for producing polymer powders(comprising acid copolymers and ionomers), and powder coatingcompositions are known (U.S. Pat. Nos. 3,933,954; 3,959,539; 4,056,653;4,237,037; 5,344,883; 6,107,412; 6,132,883; 6,284,311; 6,544,596;6,680,082; and EP1169390). Preferably, the grafted polyolefincomposition is cryogenically (for example, with liquid nitrogen as thecooling medium) ground into a powder. Physically grinding the graftedpolyolefin composition creates irregularly shaped particles of size andshape suitable for achieving constant flow through the applicationequipment. Preferably, the grafted polyolefin composition powder has aparticle size or average particle size of about 20 to about 500 μm. Toobtain the suitable particle size, the grinding step may include asieving or classification step to eliminate large- and fine-sizedparticles. For fluid bed coating processes, the preferred particle sizeis about 75 to about 350 μm.

A method to produce a grafted polyolefin-lined metal pipe comprises (i)heating a metal pipe above the softening point of a grafted polyolefincomposition; (ii) fluidizing the grafted polyolefin composition in theform of a powder; (iii) supplying the fluidized grafted polyolefinpowder to the inside of the heated metal pipe until the desired graftedpolyolefin thickness is achieved; and (iv) allowing the metal pipe tocool.

The heated metal pipe may be in a vertical orientation or a horizontalorientation during step (iii). The heated metal pipe may be rotatedduring step (iii). For example, the heated metal pipe may be rotated ata rate to force the polyolefin powder to the inside diameter of themetal pipe during step (iii).

The powder coating process comprises heating the metal pipe to atemperature above the softening point of the grafted polyolefincomposition and supplying a fluidized powder of the grafted polyolefincomposition into the heated pipe for a time sufficient to provide thedesired grafted polyolefin coating thickness. The metal pipe ispreferably heated to the temperature range of about 150 to about 400°C., preferably about 200 to about 350° C. and most preferably about 250to about 300° C. The metal pipe may be heated as described above and theheating may be discontinued throughout the remainder of the process orthe metal pipe may be continuously heated throughout the process.Portions of the pipe may be selectively heated. For example, in afluidized bed method (see below) the metal pipe may be incrementallyheated from the top to the bottom to cause the coating to formsequentially from the top to the bottom. Conversely, the metal pipe maybe heated from the bottom to the top.

The grafted polyolefin coating may be self-adhered to the metal pipe orthe interior surface of the metal pipe may be treated with adhesionprimers, coatings and layers. The use of adhesion promoting primers andcoupling agents for pipe powder coatings is known (U.S. Pat. Nos.3,016,875; 4,048,355; and 4,481,239).

Pipe powder coating methods may include descaling, degreasing andcleaning the interior of the metal pipe, as described above. Theportions of the pipe which are not desired to be coated, for example themetal pipe ends which are meant to be joined together to form thepipeline, may be masked. If desired, prior to feeding the powder, anadhesive primer, coating or layer may be applied to the interior surfaceof the metal pipe in the form of a solution or solid (powder) to provideenhanced interlayer adhesion. The metal pipe is then heated as describedabove. The metal pipe temperature may be varied as desired during thecoating operation. Preferably, the heated metal pipe may be rotatedalong its cylindrical axis at a rate of about 1 to about 300 rpm, morepreferably about 10 to about 80 rpm. The metal pipe may be rotatedslowly to provide good, even coverage of the powder coating or may berotated fast enough to force the powder to the interior surface of thepipe. The metal pipe may be in a vertical orientation or preferably in ahorizontal orientation. If a multilayer coating is desired, differentpolymeric composition powders may be fed sequentially to provide thedifferent coating layers at the thickness desired. At any stage of theprocess, abrasion-resistant particles, such as described above asfillers, may be fed into the interior of the metal pipe, eitherindividually or in combination with the powder. For example, theabrasion-resistant particles may be overcoated onto the hot coatingwhile it is still soft and tacky so that the particles adhere to theinterior surface of the coating. The coated metal pipe is then allowedto cool to ambient temperatures. If desired, any coating surfaceroughness may be smoothed through a post-coating operation, such as byhot gas, flame or oven post-treatments.

In a fluidized bed method, the powder is fed with pressurized gas, suchas compressed air, nitrogen or argon, from a fluidized bed of the powderinto the interior of the hot metal pipe. Alternatively, the hot metalpipe may be placed above the fluidized bed and the fluidized bed allowedto expand into the interior of the hot metal pipe to be coated. As thepowder contacts the heated interior surface of the metal pipe, thematerial coalesces and flows to form a continuous, fused coating. Thepowder is fed from the fluidized bed until a continuous, uniform coatingof the desired thickness is achieved.

In a spray coating method, a spray nozzle, preferably with a deflectordisc to force the powder radially out onto the metal pipe interiorsurface, supported on an extensible boom, is inserted down thecenterline of the metal pipe interior. The powder may be fed withpressurized gas, such as compressed air, nitrogen or argon, from afluidized bed of the powder. Alternatively, the powder may be deliveredfrom a bin to a vibrating feeder into a hopper and then conveyed to thespray nozzle with a pressurized gas. During the coating operation, thespray nozzle, the metal pipe or both may be moved to ensure uniformcoating over the interior surface of the pipe. Multiple coats may beapplied to provide the desired coating thicknesses.

The grafted polyolefin composition powder may be applied to the insidemetal pipe surface through electrostatic spraying processes. Forelectrostatic spraying applications, the preferred particle size isabout 20 to about 120 μm. Preferably, the metal pipe is preheated abovethe softening point of the grafted polyolefin composition as describedabove. In electrostatic spraying processes, the grafted polyolefinpowder is fed out of a reservoir, such as a fluidized bed, to a spraygun by air pressure. A high voltage, low amperage electrostatic chargeis applied to the grafted polyolefin powder by a transfer of electronsfrom the spray gun to the powder. The charged powder is sprayed onto thecleaned inside surface of the preheated, grounded metal pipe to form thegrafted polyolefin coating. Several passes may be required to build upto the desired thickness of the grafted polyolefin coating.

The grafted polyolefin composition coating may be applied to the metalpipe by thermal spraying processes, such as flame (combustion) spraying,two wire arc spraying, plasma spraying, cold spraying and high velocityoxy-fuel spraying. Preferably, the thermal spraying process is a flamespraying process. The grafted polyolefin composition may be in the formof a wire or a rod to serve as a feedstock for flame spraying processes,or it is a powder with preferred particle size of about 1 to about 50μm. The grafted polyolefin powder is fed to the flame spraying gun in astream of an inert gas (such as argon or nitrogen) and fed into a flameof a fuel gas (such as acetylene or propane) and oxygen. The graftedpolyolefin powder is melted in the flame and with the help of a secondouter annular gas nozzle of compressed air is sprayed onto the cleanedinside surface of the preheated metal pipe to form the graftedpolyolefin coating. Several passes may be required to build up to thedesired thickness of the grafted polyolefin coating. Alternatively, thegrafted polyolefin powder may be fed to the flame spray gun using aventuri effect sustained by the fuel gas flow.

The grafted polyolefin compositions may be too soft for the formation ofsuitable powder to support powder-based processes. Even if suitablepowder were produced from the grafted polyolefin compositions, thepowder may tend to mass (stick together). Powder-based processes toproduce the pipe are therefore not preferred.

The grafted polyolefin-lined metal pipe may be produced by processessimilar to the above mentioned rotational or slush molding processes.The grafted polyolefin composition may be in the form of powder,microbeads or pellets. The coating process comprises heating the metalpipe to a temperature above the softening point of the graftedpolyolefin composition, horizontally rotating the pipe and supplying thegrafted polyolefin composition into the heated pipe for a timesufficient to provide the desired grafted polyolefin coating thickness.The metal pipe may be preheated (such as in an oven), may be constantlyheated during the process or both. The grafted polyolefin compositionmay be fed all at once, batchwise or continuously to the rotating heatedmetal pipe. After an even coating of the desired thickness of thecomposition is applied to the inner surface of the metal pipe, the pipeis cooled.

The pipes described herein provide high abrasion-resistance andcorrosion resistance for the conveyance of solids and slurries such asfound in the agriculture, food and mining industries. The graftedpolyolefin layer in the pipes provides very long lifetime, especiallydesirable for those industries that require long service lifetime due tothe great maintenance and replacement complexity and cost. For example,oil slurry mining operations require kilometers of slurry pipelines inextreme environments, such as northern Alberta, Canada, so extended pipelifetime is very desirable.

A method for transporting an comprises obtaining a pipe- or tube-formedarticle as described above; preparing an composition suitable forflowing through the article; flowing the composition into one end of thepipe- or tube-formed article and receiving the composition out of theother end of pipe- or tube-formed article. The abrasive materialcomposition may be moved through the pipe by any motive force such asgravity and/or the action of a pump such as a jet pump.

The abrasive material composition may be a slurry, such as a combinationof water, oil, air, emulsified materials, particulates, solids and/orthe like. A slurry of note is oil sand slurry. In some cases, theabrasive material, such as oil sand slurry, may be at a temperature ofabout 30° C. or greater, of about 40° C. or greater, or about 50° C. orgreater. Oil sand slurries may be prepared as described in, for example,US2006/0249431. The oil sand slurry may be optionally conditioned bytransport through the pipe- or tube-formed article, such conditioningcomprising for example lump digestion, bitumen liberation, coalescenceand/or aeration. Pumping the slurry through a pipeline over a certainminimum distance (such as at least one kilometer, preferably at leasttwo kilometers), allows for conditioning the slurry. This is due to theincreased time (such as 10 minutes or greater) in the pipeline, whichallows transport through the pipeline to replace conditioning of the oilsand in a batch tumbler. In a low energy extraction process, the minedoil sand is mixed with water in predetermined proportions near the minesite to produce a slurry containing entrained air with density of 1.4 to1.65 g/cc and preferably a temperature of 20-40° C. Pumping the slurrythrough a pipeline having a plurality of pumps spaced along its length,preferably adding air to the slurry as it moves through the pipeline,conditions the slurry for further operations to extract bitumen from theslurry.

EXAMPLES

The following Examples are intended to be illustrative of the invention,and are not intended in any way to limit its scope.

Melt Index (MI) was measured by ASTM D1238 at 190° C. using a 2160 g,unless indicated otherwise. A similar ISO test is ISO 1133. Shore Ahardness was measured according to ASTM D2240, ISO 868.

Materials Used

GPO1: high density polyethylene (density 0.960 g/cc) grafted with 0.9 wt% maleic anhydride, with MI of 2 g/10 min and Shore A hardness of 98.

GPO2: poly(ethylene-co-hexene) (density 0.918 g/cc) grafted with 1.8 wt% maleic anhydride, with MI of 2 g/10 min and Shore A hardness of 96.

GPO3: poly(ethylene-co-hexene) (density 0.918 g/cc) grafted with 0.95 wt% maleic anhydride, with MI of 2.7 g/10 min and Shore A hardness of 95.

GPO4: an EPDM (density of 0.882 g/cc) grafted with 0.5 wt % maleicanhydride with MI of 23 g/10 min and Shore A hardness of 65.

GPO5: poly(ethylene-co-butene) (density 0.873 g/cc) grafted with 0.9 wt% maleic anhydride, with MI of 3.7 g/10 min and Shore A hardness of 70.

GPO6: poly(ethylene-co-octene) (density 0.863 g/cc) grafted with 0.9 wt% maleic anhydride, with MI of 1.6 g/10 min and Shore A hardness of 60.

ACR: a poly(ethylene-co-n-butylacrylate-co-methacrylic acid) containing23 wt % n-butylacrylate and 9 wt % methacrylic acid with MI of 5 g/10min.

EO: a metallocene-catalyzed ethylene-octene copolymer plastomer sold asEXACT 5361 by ExxonMobil Chemical Company, Houston, Tex. (ExxonMobil).

EP1: a metallocene-catalyzed ethylene-propylene copolymer, sold asVISTALON EPM 722 by ExxonMobil.

EP2: a metallocene-catalyzed ethylene-propylene copolymer, sold asVISTAMAXX VM1100 by ExxonMobil.

EP3: EP2 grafted with 2 wt % maleic anhydride.

EPDM: a metallocene-catalyzed ethylene-propylene-diene copolymer, soldas VISTALON 5601 by ExxonMobil.

HDPE1: a high density poly(ethylene).

HDPE2: a high density poly(ethylene) grafted with 1.5 wt % maleicanhydride. S: a styrene block copolymer sold as KRATON G7705-1 by KratonPolymers, Houston, Tex. (Kraton).

SBS: a styrene-butadiene-styrene block copolymer with a melt index of 3g/10 min at 200° C./5 kg, sold as KRATON D1153E (Kraton).

SEBS 1: a styrene-ethylene/styrene block copolymer with a melt index of5 g/10 min at 230° C./5 kg, sold as KRATON G1652M (Kraton).

SEBS 2: a styrene-ethylene/styrene block copolymer grafted with 1.7 wt %maleic anhydride, sold as KRATON FG1901X (Kraton).

SEBS 3: a styrene-ethylene/styrene block copolymer grafted with 1 wt %maleic anhydride, sold as KRATON FG1924X (Kraton).

SIS: a styrene-isoprene-styrene block copolymer with a melt index of 3g/10 min at 200° C./5 kg, sold as KRATON D111K (Kraton).

EP 3 is an EP 2 grafted with 2 wt % maleic anhydride.

Thickness and diameter in the following tables, unless specificallyindicated, are in inches.

Comparative Example CE 1 and Examples 1-7

Abrasion resistance was assessed according to the following procedure.Wear test coupons, 50 mm by 50 mm by 6.35 mm thick, were cut frominjection molded plaques of the grafted polyolefins summarized inTable 1. The wear test coupons were dried in a vacuum oven (20 inchesHg) at a temperature of 35° C. until the weight loss was less than 1mg/day and weighed. The wear test coupons were mounted in a test chamberand a 10 wt % aqueous sand (AFS50-70 test sand) slurry at roomtemperature (20-25° C.) was impinged on the wear test coupon through aslurry jet nozzle positioned 100 mm from its surface with a diameter of4 mm at a slurry jet rate of 15-16 meters/second with a slurry jet angleof 90° relative to the surface plane for 2 hours. Example 6 wasperformed with the 10 wt % aqueous sand slurry at a temperature of 30°C. Example 7 was performed with the 10 wt % aqueous sand slurry at atemperature of 20° C. The wear test coupons were then removed and driedin a vacuum oven (20 inches Hg) at room temperature for at least 15hours and then reweighed. The results are reported in Table 1.

TABLE 1 Initial Final Weight Weight Weight Loss Example Material (g) (g)(g) Reduction (%)¹ CE 1 GPO1 7.9861 7.9485 0.0376 0 1 GPO2 7.2931 7.28110.0120 68 2 GPO3 7.6168 7.6054 0.0114 70 3 GPO4 7.4515 7.4473 0.0042 894 GPO5 8.0462 8.0462 0.0000 100 5 GPO6 7.6168 7.6168 0.0000 100 6 GPO58.0482 8.0462 0.0020 100 7 GPO6 7.6170 7.6168 0.0002 100 ¹The reductionis normalized over the weight loss of Example CE1

Examples 8-16

The grafted polyolefin pipes summarized in Table 2 are made from thematerials listed by conventional pipe extrusion and sizing methods withmelt extrusion temperatures in the range from about 150° C. to about225° C. The pipes are cut into 20 foot lengths. “OD”=outer diameter.

TABLE 2 Example Material OD thickness Thickness Example Material ODthickness Thickness 8 GPO5 20 0.5 13 GPO6 32 1.5 9 GPO6 24 1.0 14 GPO426 0.4 10 GPO5 28 2.0 15 GPO5 30 1.0 11 GPO2 22 0.38 16 GPO6 34 1.8 12GPO3 26 0.75

Examples 17-22

The grafted polyolefin bilayer pipes summarized in Table 3 are made fromthe materials listed by conventional multilayer pipe extrusion andsizing methods with melt extrusion temperatures of about 150° C. toabout 225° C. The pipes are cut into 20 foot lengths.

TABLE 3 Inner Layer Outer Layer Example Material Thickness MaterialThickness OD thickness 17 GPO5 0.5 ACR 0.25 20 18 GPO3 1.0 EPDM 0.4 2419 GPO5 2.0 HDPE 1 0.5 28 20 GPO6 0.38 SEBS 2 0.2 22 21 GPO4 0.75 SEBS 30.3 26 22 GPO6 1.5 HDPE 2 0.5 32

Examples 23-31

Multilayer grafted polyolefin pipes are made from the materialssummarized in Table 4 by conventional multilayer pipe extrusion andsizing methods with melt extrusion temperatures of about 150° C. toabout 225° C. The tielayer is approximately 1-2 mils thick (0.026-0.051mm) and is positioned between the inner layer and outer layer to provideadhesion. All Examples also have a tielayer on the outside surface ofthe outer layer: the structure of the pipe is tielayer/outerlayer/tielayer/inner layer. The pipes are cut into 20-foot lengths.

TABLE 4 Inner Layer Tie Layer Outer Layer OD Example Material ThicknessMaterial Material Thickness thickness 23 GPO5 0.5 EP 3 EO 0.25 20 24GPO3 1.0 EP 3 EP 1 0.4 24 25 GPO6 2.0 EP 3 EP 2 0.5 28 26 GPO4 0.38 EP 3EPDM 0.2 22 27 GPO5 0.75 HDPE 2 HDPE 1 0.3 26 28 GPO5 1.5 SEBS 2 S 0.532 29 GPO6 0.45 SEBS 3 SBS 0.2 26 30 GPO6 1.0 SEBS 2 SEBS 1 0.1 30 31GPO4 1.8 SEBS 2 SIS 0.3 34

Examples 32-38

The grafted polyolefin pipe-lined carbon steel pipes summarized in Table5 are made by inserting the grafted polyolefin pipes listed into 20-footlengths of carbon steel pipes with 0.75-inch wall thickness and theinner diameter (ID) listed. Prior to lining the pipe, the interiorsurface of the carbon steel pipe is sandblasted and degreased.

TABLE 5 Grafted Carbon Grafted Carbon polyolefin steel pipe polyolefinsteel pipe pipe (ID pipe (ID Example (Example) thickness) Example(Example) thickness) 32 8 22 36 22 34 33 12 28 37 26 24 34 15 32 38 2928 35 18 26

Examples 39-46

The grafted polyolefin pipe-lined pipelines summarized in Table 6 aremade by thermally fusing the ends (“butt fusion”) of the graftedpolyolefin pipes listed through conventional methods and inserting thepolymeric pipes into the carbon steel pipes with 0.75-inch wallthickness and the length and the ID listed. Prior to lining the pipe,the interior surface of the carbon steel pipe is sandblasted anddegreased.

TABLE 6 Grafted Carbon Grafted Carbon polyolefin steel pipe polyolefinsteel pipe pipe (ID pipe (ID Example (Example) thickness) Example(Example) thickness) 39 9 26 1 43 19 40 11 24 2 44 24 41 16 36 3 45 3942 17 22 0.5 46 30

Examples 47-68

The grafted polyolefin pipe-lined carbon steel pipes summarized in Table7 are made by heating 20 foot lengths of carbon steel pipes with0.75-inch wall thickness and the ID listed to 200° C.; inserting thegrafted polyolefin pipes listed into the hot carbon steel pipes; andallowing the lined pipe to cool to ambient temperatures. Prior to liningthe steel pipe, the interior surface is sandblasted and degreased.

TABLE 7 Grafted Carbon Grafted Carbon polyolefm steel pipe polyolefinsteel pipe pipe (ID pipe (ID Example (Example) thickness) Example(Example) thickness) 47 8 20 58 21 26 48 9 24 59 22 32 49 10 28 60 23 2050 11 22 61 24 24 51 12 26 62 25 28 52 13 32 63 26 22 53 14 26 64 27 2654 15 30 65 28 32 55 16 34 66 29 26 56 17 20 67 30 30 57 20 22 68 31 34

Preparative Examples PE1-PE9

Grafted polyolefin sheets with a thickness of 0.125 inch and a width of9 feet are made from the materials summarized in Table 8 by conventionalsheet extrusion methods with melt extrusion temperatures of about 150°C. to about 225° C. The sheets are plied together to provide thedescribed thickness by conventional calendering processes.

TABLE 8 Preparative Sheet Preparative Sheet Example Material ThicknessExample Material Thickness PE1 GPO5 0.5 PE6 GPO4 1.5 PE2 GPO5 1.0 PE7GPO6 0.5 PE3 GPO5 2.0 PE8 GPO6 1.0 PE4 GPO6 0.25 PE9 GPO6 1.75 PE5 GPO30.75

Examples 69-77

The grafted polyolefin-lined carbon steel pipes summarized in Table 9are made by inserting the grafted polyolefin sheets listed into 20-footlengths of carbon steel pipes with 0.75-inch wall thickness with the IDlisted. Prior to lining the pipe, the interior surface of the carbonsteel pipe is sandblasted and degreased. The grafted polyolefin sheetsare cut down in size to fit the carbon steel pipe and the seam is buttwelded by thermally fusing the ends (“butt fusion”). The graftedpolyolefin-lined carbon steel pipe is heated to 200° C. while beingrotated in the horizontal axis, and then the lined pipe is cooled toambient temperatures.

TABLE 9 Grafted Carbon Grafted Carbon polyolefin steel pipe polyolefinsteel pipe pipe (ID pipe (ID Example (Example) thickness) Example(Example) thickness) 69 PE1 22 74 PE6 24 70 PE2 28 75 PE7 28 71 PE3 3276 PE8 20 72 PE4 26 77 PE9 30 73 PE5 34

The invention claimed is:
 1. A pipe- or tube-shaped article having aninnermost layer wherein the innermost layer has a thickness of about 3.2to about 102 mm and comprises a grafted polyolefin, wherein the graftedpolyolefin is the only polymer in the innermost layer; the graftedpolyolefin is produced from a parent polyolefin comprising ethylene andan α-olefin with 3 to 20 carbons and grafted with about 0.005 to about10 wt % of an α,β-ethylenically unsaturated carboxylic acid oranhydride; and the innermost layer does not comprise a tackifier.
 2. Thearticle of claim 1 wherein the grafted polyolefin is produced from aparent polyolefin comprising ethylene and an α-olefin with 3 to 20carbons; and the parent polyolefin has a density of about 0.88 g/cc(ASTM D-792) or less.
 3. The article of claim 1 wherein the innermostlayer has a reduction in weight loss by at least 50% when exposed to asand slurry stream for 2 hours, as compared to an innermost layerproduced from a high density polyethylene grafted with 0.9 weight %maleic anhydride.
 4. The article of claim 2 wherein the innermost layerhas a reduction in weight loss by at least 60% when exposed to a sandslurry stream for 2 hours, as compared to an innermost layer producedfrom a high density polyethylene grafted with 0.9 weight % maleicanhydride.
 5. The article of claim 2 wherein the parent polyolefin has adensity of about 0.87 or lower; and the α,β-ethylenically unsaturatedcarboxylic acid or anhydride is selected from the group consisting ofmaleic anhydride, maleic acid, fumaric acid, acrylic acid, methacrylicacid, itaconic anhydride, itaconic acid, citraconic acid, citraconicanhydride, crotonic acid, crotonic anhydride, methyl crotonic acid,cinnamic acid, endo-bicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic acid,endo-bicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic anhydride,cis-4-cyclohexene-1,2-dicarboxylic acid,cis-4-cyclohexene-1,2-dicarboxylic anhydride and mixtures thereof. 6.The article of claim 5 wherein the α,β-ethylenically unsaturatedcarboxylic acid or anhydride is maleic anhydride and the innermost layerhas a thickness of about 6.3 to about 76 mm.
 7. A method comprisinglaying up a pre-formed film or sheet into a preformed metal or plasticpipe to produce a grafted polyolefin-lined metal or plastic pipe whereinthe film or sheet is the same as the innermost layer recited in claim 2.8. The method of claim 7 further comprising heating the metal or plasticpipe above the softening point of the grafted polyolefin and allowingthe metal or plastic pipe to cool to produce the graftedpolyolefin-lined metal or plastic pipe.
 9. The method of claim 7 furthercomprising, prior to the laying up, producing a pipe- or tube-shapedarticle from the preformed film or sheet and inserting the pipe- ortube-shaped article into the interior of the pipe.
 10. The method ofclaim 9 further comprising producing an abrasive material; flowing theabrasive material into one end of the pipe- or tube-shaped article;receiving the abrasive material out of the other end of the pipe- ortube-shaped article for transporting the abrasive material therebytransporting the abrasive material.
 11. The method of claim 10 whereinthe abrasive material is oil sand.
 12. A pipe- or tube-shaped articlecomprising an innermost layer and an outer layer wherein the innermostlayer has a thickness of about 0.001 to about 102 mm and comprises agrafted polyolefin, wherein the grafted polyolefin is the only polymerin the innermost layer; the grafted polyolefin is produced from a parentpolyolefin comprising ethylene and an α-olefin with 3 to 20 carbons andgrafted with about 0.005 to about 10 wt % of an maleic anhydride; theparent polyolefin has a density of about 0.87 or lower; the innermostlayer does not comprise a tackifier; and the outer layer comprises afiber reinforcement material and optionally a thermoset resin.
 13. Thearticle of claim 12 further comprising an intermediate layer between theinnermost layer and the outer layer and the intermediate layer comprisesrubber, elastomer, thermoplastic elastomer, acid terpolymer, ionomerterpolymer, or mixtures of two or more thereof.
 14. The article of claim12 further comprising an outermost layer which comprises carbon steel,stainless steel, cast iron, galvanized steel, aluminum, copper, oralloys of two or more thereof.
 15. The article of claim 14 furthercomprising an intermediate layer between the innermost layer and theouter layer and the intermediate layer comprises rubber, elastomer,thermoplastic elastomer, acid terpolymer, ionomer terpolymer, ormixtures of two or more thereof.
 16. A pipe- or tube-shaped articlehaving an innermost layer wherein the innermost layer has a thickness ofabout 3.2 to about 102 mm and comprises a grafted polyolefin, whereinthe grafted polyolefin is the only polymer in the innermost layer; thegrafted polyolefin is produced from a parent polyolefin comprisingethylene and an α-olefin with 3 to 20 carbons and grafted withanhydride; and the innermost layer does not comprise a tackifier. 17.The article of claim 16 wherein the innermost layer has a reduction inweight loss by at least 70% when exposed to a sand slurry stream for 2hours, as compared to an innermost layer produced from a high densitypolyethylene grafted with 0.9 weight % maleic anhydride; the graftedpolyolefin is produced from a parent polyolefin comprising ethylene andan α-olefin with 3 to 20 carbons; and the parent polyolefin has adensity of about 0.88 g/cc (ASTM D-792) or less.
 18. The article ofclaim 17 wherein the innermost layer has a reduction in weight loss byat least 80% when exposed to a sand slurry stream for 2 hours, ascompared to an innermost layer produced from a high density polyethylenegrafted with 0.9 weight % maleic anhydride; the innermost layer has athickness of about 6.3 to about 76 mm; the parent polyolefin has adensity of about 0.87 or lower; and the α,β-ethylenically unsaturatedcarboxylic acid or anhydride is maleic anhydride.
 19. The article ofclaim 18 further comprising, based on the total weight of the graftedpolyolefin, from about 0.1 wt % to about 80 wt % of a filler.